Valve tappet



J. H. HOERN March 14, 1939.

VALVE TAPPET Filed May 7, 1938 INVENTOR BY I TORYNEY Patented Mar. 14, 1939 UNITED STATES VALVE.

TAPPET Joseph H. Hoern, Birmingham, Mich., assignor to Eaton Manufacturing Company,

Cleveland,

Ohio, a corporation of Ohio Application May 7, 1938, Serial No. 206,555

8 Claims.

This invention relates to valve tappets for internal combustion engines, the principal object being the provision of a highly efiicient tappet of this general type that is extremely economical to 5 manufacture, that is strong and is efiicient in operation.

Other objects of the invention include the provision of a valve tappet made up of a plurality of independently formed parts and in which the major portion of the exterior surfaces of the tappet are hardened; the provision of a valve tappet structure including an intermediate portion of non-hardening material and oppositely extending bearing portions of hardened material; the provision of a valve tappet structure including a pair of spaced hardened body portions separated and secured relative to one another by an intermediate portion of machinable material formed to provide an oil receiving groove on its exterior surface and a guiding surface on its interior surface; and the provision of a valve tappet including a cup-shaped portion of hardened material the open end of which is constricted by means of a member of comparatively soft or machinable material secured thereto.

The above being among the objects of the present invention the same consists in certain novel features of construction and combinations of parts to be hereinafter described with reference to the accompanying drawing, and then claimed, having the above and other objects in view.

In the accompanying drawing which illustrates a suitable embodiment of the present invention and in which like numerals refer to like parts throughout the several different views,

Fig. 1 is a vertical sectional view taken axially through a valve tappet constructed in accordance with the present invention;

Fig. 2 is a transverse sectional view taken on the line 22 of Fig. 1;

Fig. 3 is an exploded side elevational view of the various independently formed parts which are assembled together to form the valve tappet shown in the preceding figures;

Fig. 4 is a view similar to Fig. l but illustrating a suitable type of hydraulic clearance adjusting unit in operative position within the tappet.

Referring to the drawing and particularly to Fig. 1 the tappet shown is an integral structure made up by suitably welding together four initially'independently formed. parts, namely an annular intermediate member ID, oppositely extending relatively thin walled hollow cylindrical main body portions 12 and I4 welded .to the respectively opposite ends of the member Hi, and

a cam contact and member l6 closing the lower or outer end of the portion l4. All of these members are of circular conformation as indicated in Fig. 2. The intermediate member I is provided with a relatively deep peripheral groove l8 in its exterior surface intermediate the ends thereof, the purpose of which is to provide a means for receiving a supply of oil under pressure during operation of the tappet in an internal combustion 10 engine and to convey it to the opening 20 extending between the groove I8 and the lower interior portion of the tappet as illustrated in Fig. 1

in order to maintain the lower portion of the tappet full of oil for a purpose which will hereinafter be more fully described.

The intermediate member ID is provided with an axially concentric bore 22, of reduced dimensions compared to the inner diameters of the portions l2 and I4, enlarged at its. upper end as at 24 to provide a radial shoulder 26 and the member ID is preferably axially relieved radially outwardly of the shoulder 26 as shown. The bore 22 is adapted to slidably receive an automatic hydraulic valve clearance adjusting unit such as the unit indicated generally at 28 in Fig. 4 and while in the broader aspects of the invention any suitable type of hydraulic unit 28 may be employed in conjunction with the tappet that shown in Fig. 4 is included in the subject-matter of the 30 co-pending application for Letters Patent of the United States of Carl Voorhies for improvements in Internal combustion engine, filed April 14, 1938, and serially numbered 202,022, and owned by the assignee of the present invention. As far as the present invention is concerned all that is necessary to note in connection-with the hydraulic unit 28 is that its cylindrical main body portion is slidably received in the bore 22, it has an outwardly projecting annular flange 30 at its upper end which is received within the enlarged portion 24 of the bore 22 in radially spaced relation with respect to the circumferential walls thereof, and an axial face of which flange 30 abuts against the shoulder 26 to limit downward movement of the unit 28 in the tappet to a position in which its lower end is upwardly spaced from the inner face of the end member IS.

The main body portions l2 and [4 are imperforate hollow cylinders of relatively thin wall construction with an internal diameter substantially greater than the hydraulic unit 28 so that a chamber 32 is formed in the lower portion of the tappet between the main body member l4 and the lower end of the unit 28 and it is this chamber that is adapted to be maintained full of oil conducted thereto through the opening 20 previously described so as to provide a reservoir of oil necessary for the operation of the hydraulic unit 28. It may be noted that the lower face of the intermediate member I within the chamber is beveled as at 34 thus to provide a means for collecting any air which becomes entrapped within the chamber 32 at the highest point in the chamber 32 and in a position where it may escape upwardly between the hydraulic unit 28 and the bore 22.

In the preferred form of the tappet thus shown the portions I2 and I4 and the end member I6 are preferably formed of a material which is hardenable in and of itself upon heating and quenching. Because the end member I5 is adapted for direct contact with the valve operating cam it is preferable that it be of a harder nature than the members I2 and I4 which simply guide the tappet in its reciprocating movement. Accordingly, the members I2 and I4 may be made of a material which upon heating and quenching will have a hardness of approximately 40 Rockwell, Class C and as illustrative of one type of steel that has been found satisfactory for use in this connection the analysis of SAE steel #1035 is here set out.

gated tubes with the opposite edges of the strips brought into abutting relationship and welded together in accordance with certain conventional methods of forming steel tubes, pipes or the like, and then sections of the desired length cut off. On the other hand each of the portions I2 and I4 may be made from a rectangular piece of sheet metal of the dimensions required to make a hollow tube of the dimensions of these parts and simply rolling this piece of sheet metal up to bring the opposite edges into abutting relationship and then welding the said edges together.

By making the portions I2, I4 and I6 of a material that is harden-able upon heating and quenching an intermediate member ID of a material that is not thus hardenable, the portions I2 and I4 may be welded to the intermediate member I0 and the end member I6 welded to the remaining end of the member I4, the entire assembly heated and quenched, and then the intermediate member l0 machined after the hardening operation to provide the groove I8 and bores 22 and 24. By this method of operation the chamber 32 is completely closed during the hardening operation and consequently its interior surfaces are free from scale and other impurities or foreign material such as usually forms during a hardening operation.

Carbon Manganese Phosphorus Sulphur Balance Percent Percent Perccrzt Percent 0. 304). 40 0. 60-0. 00 0. 045 maximum 0.055 maximum Principally iron The member IS in such case may suitably be made from a steel of which SAE steel #52100 having the following composition is an example.

The tappet shown may also be constructed by forming all of the portions I0, I2, I4 and I6 of a material not having the characteristic of becom- Carbon Manganese Phosphorus Sulphur Chromium Balance Percent Percent Fe rcc'nt Percent Percent 0. 95-1. 10 0. 204). 50 0. 030 maximum 0. 035 maximum 1. 1. 50 Principally iron The intermediate member III in such case is preferably formed of a type of steel that does not have the characteristic of becoming hard upon heating and quenching and as illustrative of a suitable type of steel to employ for this member the analysis of SAE steel #1020 is here set out.

ing hardened upon heating and quenching so that after all of the parts have been welded together the entire assembly may be carbonized in a suitable or conventional manner and then hardened as a whole although where the member ID in such case is initially made solid it will first Carbon Manganese Phosphorus Sulphur Balance Percent Percent Percent Percent 0. 154). 0. -0. 60 0.045 maximum 0.055 maximum Principally iron In the broader aspects of the invention the members I2 and I4 may be made in any suitable manner as for instance machined out of solid stock, or formed of lengths of seamless steel tubing of the desired composition but preferably these members are formed from sheet metal which has been formed into cylindrical conformation, and having its abutting edges welded as at 36 in Fig. 2. in constructing the portions or members I2 and I4 from sheet metal as described, strips of sheet metal of suitable width may be formed into elonbe necessary to machine away the carbonized surfaces of that portion of it which it is later required to machine. In such case the members I0, I2 and I4 will be formed from a steel such as the SAE steel #1020 the analysis of which has been previously given herein. Under such cir-- cumstances the end member I6 will not possess a sufiicient degree of hardness if formed from SAE steel #1020 and in such case it will be preferable to form the end member I6 from a steel of which SAE steel #3115 is an example and the analysis of which is as follows.

with, and an end member secured to and closing the remaining end of one of said tubes.

Carbon Manganese Phosphorus Sulphur Nickel Balance Percent Percent Percent Percent Percent Percent 0. 10-0. 20 0. 30-0. 60 0.040 maximum 0.050 maximum 1. 00-1. 50 0. 45-0. 75 Principally iron If it is desired to form the members I0, I2 and M from a material such as the SAE steel #1020 previously described and requiring carbonization before heating and quenching to obtain a desired hardness and it is desired to form the erid member [6 from a steel having the characteristics of becoming hardened upon heating and quenching without carbonization, for instance such as SAE steel #52100 above described, then it will be necessary to weld the members l0, l2 and M together, and carbonize them before welding the end member It thereto, after which the entire assembly may be subjected to a suitable heating and quenching operation to obtain the desired surface hardness thereof.

The method of making the tappet herein shown and described forms no part of the present invention but does form the subject-matter of my co-pending application for Letters Patent of the United States for improvements in Method of forming valve tappets, filed April 2'7, 1938, and serially numbered 204,692. From the above it will be understood that because of the ability of forming the parts l2 and 14 from tubular stock of constant wall thickness throughout and particularly because of the ability to employ welded steel tubes of conventional construction, the valve tappet shown is extremely economical to manufacture, because of its hardened wearing surfaces it provides a valve tappet having exceedingly long life, and because of its Welded construction provides a valve tappet of exceptional strength and lightness.

Formal changes may be made in the specific embodiment of the invention described Without departing from the spirit or substance of the broad invention, the scope of which is commensurate with the appended claims.

What I claim is:

1. A valve tappet comprising, in combination, a pair of tubular members of substantially uniform thickness throughout arranged in aligned and axially spaced relation, an intermediate body member having a restricted bore arranged between and in aligned relation with respect to said body member and rigidly secured thereto, and an end member secured to and closing the remaining end of one of said body members.

2. A valve tappet comprising, in combination, an intermediate body member of annular formation, a pair of sheet metal tubes of uniform wall thickness secured to the respective opposite ends of said intermediate body member, and an end member secured to the remaining end of one of said tubes.

3. A valve tappet comprising, in combination, an intermediate body member formed of a material having the characteristic of remaining machinable upon heating and quenching, a pair of tubes each formed from a material having the characteristic of becoming hardened upon heating and quenching each having an end thereof fixed to the respectively opposite ends of said intermediate body portion in axial alignment there- 4. A valve tappet comprising, in combination, an annular intermediate body member formed of a material having the characteristic of remaining machinable upon heating and quenching, a pair of tubular members of substantially uniform Wall thickness formed of a material having the characteristic of becoming hardened upon heating and quenching each secured at one of its ends to the respectively opposite ends of said intermediate body portion, and an end member formed of a material having the characteristic of becoming hardened to a greater extent than said tubes upon heating and quenching secured to and closing the remaining end of one of said tubes.

5. A valve tappet comprising, in combination, a pair of aligned cylindrical axially spaced hollow body portions of substantially uniform wall thickness, an intermediate body portion joining said cylindrical portions and having a peripheral a pair of sheet metal tubes arranged in axially aligned and spaced relation, the exterior surfaces of said tubes being of a relatively unmachinable nature and the interior portions thereof being of a relatively machinable nature, an intermediate body member spacing said tubes and secured thereto, and an end member secured to and closing the remaining end of one of said tubes.

7. A valve tappet comprising, in combination, a pair of sheet metal tubes arranged in axially aligned and spaced relation, the exterior surfaces of said tubes being of a relatively unmachinable nature and the interior portions thereof being of a relatively machinable nature, an intermediate body member spacing said tubes and secured thereto, and an end member of relatively unmachinable characteristics throughout secured to and closing the remaining end of one of said tubes.

3. A valve tappet comprising, in combination, a pair of cylindrical tubes arranged in axially aligned and spaced relation, an intermediate member of annular formation interposed between and rigidly securing said tubes with respect to each other, the exterior surfaces of said tubes and intermediate member being of relatively hard and unmachinable character and the interior portions thereof being of a relatively machinable nature, the surface of the bore of said intermediate member being of a relatively machinable nature, and an end member having an outer face of relatively unmachinable nature secured to and closing the remaining end of one of said tubes.

JOSEPH H. HOERN. 

